A review on the management of rinse wastewater in the agricultural sector

Pesticides have become indispensable compounds to sustain global food production. However, a series of sustainable agricultural practices must be ensured to minimize health and environmental risks, such as eco-friendly cultivation techniques, the transition to biopesticides, appropriate hygiene measures, etc. Hygiene measures should include the management of rinse wastewater (RWW) produced when cleaning agricultural equipment and machinery contaminated with pesticides (among other pollutants), such as sprayers or containers. Although some technical guidelines encourage the reuse of RWW in agricultural fields, in many cases the application of specialized treatments is a more environmentally friendly option. Solar photocatalysis was found to be the most widely studied physical-chemical method, especially in regions with intense solar radiation, generally using catalysts such as TiO₂, Na₂S₂O₈, and H₂O₂, operating for relatively short treatment periods (usually from 10 min to 9 h) and requiring accumulated radiation levels typically ranging from 3000 to 10000 kJ m⁻². Biological treatments seem to be particularly suitable for this application. Among them, biobed is a well-established and robust technology for the treatment of pesticide-concentrated water in some countries, with operating periods that typically range from 1 to 24 months, and with temperatures preferably close to 20 °C; but further research is required for its implementation in other regions and/or conditions. Solar photocatalysis and biobeds are the only two systems that have been tested in full-scale treatments. Alternatively, fungal bioremediation using white rot fungi has shown excellent efficiencies in the degradation of pesticides from agricultural wastewater. However, greater efforts should be invested in gathering more information to consolidate these technologies and expand their use in the agricultural sector.